A weakened Hurricane Matthew neared the end of its weeklong charge through Caribbean islands and along the U.S. Atlantic coast after killing nearly 1,000 people, most of them in Haiti. The storm also flattened communities and wrecked agriculture in the Dominican Republic, Jamaica, Cuba and the Bahamas.

Haiti has declared three days of national mourning, President Jocelerme Privet's office said, "in solidarity" with the parents and friends of the victims of Matthew and residents of the region who are suffering from the hurricane's impact.

Matthew is moving northeastward over North Carolina's Outer Banks with maximum sustained winds of 120 kilometers per hour - half as strong as they were a week ago.

Serious flooding was reported in many areas along a 950-kilometer stretch of the U.S. East Coast from Florida north to North Carolina. U.S. President Barack Obama declared states of emergency in four states, where at least 10 deaths were reported due to the storm.

Matthew was the most powerful storm to hit the U.S. coast in nearly a decade, and one of the longest-lasting major hurricanes on record, but damage to property was much less than had been predicted.

Casualties still rising

The hurricane was at its most powerful when it ravaged the Caribbean nearly a week ago with winds of 235 kilometers per hour. Although more than 900 deaths have been reported in Haiti, many areas of that impoverished country have not yet been thoroughly surveyed.

Haiti says 1.5 million people have been affected the the hurricane and 350,000 are in need of immediate assistance as most are homeless.

The U.S. military has been deploying aid to Haiti by air and sea; food and medicine as well as equipment, including heavy-lift helicopters, bulldozers, water-delivery vehicles and mobile operating rooms.

A woman who identified herself as Valerie walks along flooded President Street after leaving her homeless camp after Hurricane Matthew caused flooding, Oct. 8, 2016, in Savannah, Ga.

UNICEF says the conditions in Haiti are "perfect breeding grounds for waterborne diseases." Marc Vincent, UNICEF's representative in Haiti says, "Every day that goes by increases the threat of cholera."

As Matthew passed over Haiti it also raked the eastern tip of Cuba. Few reports of casualties or damage have emerged since Tuesday, but the island nation is expected to need massive quantities of relief supplies.

The Dominican Republic, which lies on the eastern half of Hispaniola Island, bordering Haiti, also felt Hurricane Matthew's power. The storm later coursed through the Bahamas before traveling north along the U.S. East Coast, slowly weakening but remaining just offshore until it finally made landfall in South Carolina Saturday.

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The catastrophic damage this week in Haiti was made worse because the impoverished country is still recovering from a devastating earthquake in 2010. Thousands of people who have been living in flimsy shelters since the earthquake saw those washed away by the hurricane, which also destroyed a bridge that is the only link between a large portion of southern Haiti and the rest of the country.

Residents and aid workers in eastern Cuba were still assessing storm damage. There were no immediate reports of casualties, but workers from a Roman Catholic charity organization spent nearly 16 hours trying to reach Baracoa, a community of 82,000 residents. Locals said the trip from Guantanamo to Baracoa normally takes just over two hours.

The Miami Herald reported that one local church official found Baracoa with ruined roads, damaged communications and neighborhoods near the coast reduced to rubble.

WATCH: video footage of devastation in Les Cayes, Haiti

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